[PATCH v2 01/10] eal: add workaround for __builtin_constant_p

[Morten Brørup]

> From: Andre Muezerie [mailto:andremue at linux.microsoft.com]
> Sent: Tuesday, 18 February 2025 17.32
> 
> There's no MSVC equivalent for compiler extension __builtin_constant_p.
> EAL already had __rte_constant which was used as a first attempt to
> workaround __builtin_constant_p when using MSVC. However, there are
> pieces of code that would benefit from being able to provide a default
> value to be used instead of it being always 0 like how it was done by
> __rte_constant.
> 
> A new macro is added here allowing such default to be provided by the
> caller.

NAK to the new macro.

Please use the sizeof() hack suggested by Stephen to provide an implementation of __rte_constant(e) for MSVC.
Here's a link to an example of the hack:
https://news.ycombinator.com/item?id=16720172